Abstract:The migratory pest brown planthopper, Nilaparvata lugens, was trapped by using ordinary incandescent light from 1977 to 2007 in Jiangkou, Guizhou Province. Population dynamics and occurrence period of the pest based on the historic data of this area was analyzed. The results showed that its first occurrence date was in late April to May and the initial outbreak date was in June to July. There were two occurrence peaks in one year: the first peak (early rice peak) appeared in late July to late August and the second peak (late rice peak) appeared in September to October. In recent years, the first appearance date, initial outbreak date and peak period had the tendency of advancing. There were obvious correlation among the catches of the peak day, the peak five-day, the peak ten-day and the seasonal total, and the correlation coefficients are 0.9579-0.9861 and 0.8675-0.9772 for early rice and late rice respectively. According to the data of 25 years, the yearly occurrence peak appeared on late rice except 5 years in the previous 15 years and all appeared on early rice in latter 10 years lacking the data of 1988 and 2000 to 2004. Taking the catches of peak five-day as the quantification index, 5 years occurred greatly, 5 years greatly to moderately, 5 years moderately, 2 years moderately to slightly and 8 years slightly. The above result is almost consistent with occurrence situation of brown planthoppers in paddy fields.